I recently completed a no-weld MBB front drive bike. Originally, I had a 26" rear wheel, had some handling issues most likely due to the trail being out of whack with the different wheel sizes. So, I threw a 24" wheel on the rear and took it for a test-ride and I think that may have straightened out the handling issue. I'm guessing that as long as the front/rear wheels are the same size, the trail is correct. While coasting down some fairly steep descents, the bike seems to remain fairly stable but still seems a little shaky. Doe's anyone find larger diameter wheels improve handling? Or am I just not yet used to the bike?
I'm guessing that as long as the front/rear wheels are the same size, the trail is correct.
Not necessarily. There are numerous bikes which roll off the assembly line with mismatched wheel sizes. Many posses excellent handling at most speeds. Irregardless of wheel size, 'trail' can usual be altered to suit the design by just bending or fabricating a new fork.
Any number of design parameters can improve or spoil a bike's demeanor, including wheel diameter. Weight distribution, wheelbase, amount of tiller, tire type and inflation pressures all effect the bike's handling to some degree. Can you post a side shot of the bike in question?
The new front triangle is from a smaller bike that used 24" wheels. The women's donor bike had 26" wheels. I didn't lengthen the wheelbase, just installed matching 24" wheels front and rear.
Yes, but the main frame was meant for a 26" front wheel. By installing a 24" front end on a 26" frame, you made the steering angle steeper, reducing trail. Going to 24" in back leveled the frame and normalized the steering angle. Your bike still has less trail than the original donor bike, but at least it's in the same ballpark now.
I went to the Rans Rally in Hays Ks the first weekend in Sept. One of the things I wanted to do was talk to Randy the owner about wheel size. Rans seems to be big on large front wheels on their long wheel base bents. I mentioned to Randy that on my Stratus with the 20" front and the 26" rear I think I have the best of both worlds. The 20" front has a lot less rotational enerta, so you can get up to speed quicker, while the 26" rear gives more speed and a better ride. Randy did admit that the 20 does give better acceleration, but seemed to really think the 26-26 made a better bike. BTW my Rans Tailwind (20-20) accelerated really fast.
At the rally, I talked to one rider that said the had a Stratus 20-26 and now rides the 26-26. Like Randy he claimed it was a better bike. But I was riding with him for quite a while, and while following, I noticed he seemed to weave (make a lot of steering corrections) far more than I was. That may just be difference in riders tho. I ride bike trails here in Lincoln a lot. I have to start and stop at a lot of street crossing, so getting back up to speed may be higher on my list of needs. So the 20 inch wheel helps me quite a bit here.